feature/vsn-bugfix - Implement manual mappers for WorkSchedule and WeeklySchedule to resolve ModelMapper ambiguity
- Replace ModelMapper usage in WorkSchedule and WeeklySchedule mapping with explicit manual conversion
- Introduce DayScheduleDTO, WeeklyScheduleDTO and corresponding mappers (DayScheduleMapper, WeeklyScheduleMapper)
- Eliminate bidirectional mapping conflicts caused by collaboratorId/collaboratorUuid in WorkScheduleDTO
- Ensure safe JPA entity construction without circular references
- Maintain existing service logic while fixing "matches multiple source property hierarchies" error